Recycling of flexible polyurethane foam scrap

Abstract

A reaction mixture containing comminuted, flexible polyurethane foam scrap is used in making new flexible polyurethane foam. The process achieves a highly satisfactory utilization of foam scrap, while providing a quality foam product.

What is claimed is: 
     
       1. In a process for preparing a flexible polyurethane foam from a foam forming reaction mixture comprising a polyol, an organic polyisocyanate, a foaming agent and a reaction catalyst, the improvement comprising blending in said reaction mixture a proportion of comminuted, flexible polyurethane foam scrap having a maximum particle size of less than about 600 microns to form a suspension in said reaction mixture, said proportion of scrap being from about 3 to about 40 parts, by weight, based on 100 parts of total polyol weight. 
     
     
       2. The process of claim 1, wherein said polyol is a polyether polyol. 
     
     
       3. The process of claim 2, wherein said reaction mixture further comprises a surfactant. 
     
     
       4. The process of claim 3, wherein said proportion ranges from about 5 to about 32 parts. 
     
     
       5. The process of claim 4, wherein said proportion ranges from about 8 to about 24 parts. 
     
     
       6. The process of claim 3, wherein said polyether polyol is an oxyalkylated polyhydric alcohol having a molecular weight of about 1,000-6,000 and said organic polyisocyanate is toluene diisocyanate. 
     
     
       7. The process of claim 6, wherein said polyether polyol is oxypropylated glycerin and said reaction mixture comprises water and a catalyst mixture of an amine and a stannous salt. 
     
     
       8. The process of claim 3, wherein said foam scrap is flexible, compression-densified polyurethane foam having a density within the range from about 1.5 to about 15 pounds per cubic foot. 
     
     
       9. The process of claim 8, wherein said foam scrap is employed in a proportion ranging from about 8 to about 24 parts, by weight, based on 100 parts of total polyol weight. 
     
     
       10. The process of claim 9, wherein said polyether polyol is an oxyalkylated polyhydric alcohol having a molecular weight of about 1,000-6,000 and said organic polyisocyanate is toluene diisocyanate. 
     
     
       11. The process of claim 10, wherein said polyether polyol is oxypropylated glycerin and said reaction mixture comprises water and a catalyst mixture of an amine and a stannous salt. 
     
     
       12. In a process for preparing a flexible, compression-densified polyurethane foam having a density within the range from about 1.5 to about 15 pounds per cubic foot prepared by (a) placing a polyurethane foam forming reaction mixture in a reaction zone and allowing the mixture to rise freely, thereby forming a partially cured cellular material, said reaction mixture being comprised of a polyol, an organic polyisocyanate, a foaming agent and a reaction catalyst;   (b) applying a compressive force to the partially cured cellular material after completion of the rise, thereby;   (c) reducing the volume of the partially cured cellular material to between about 3/4 and about 1/10 of its original volume; and   (d) removing the compressive force and completing the cure of the compressed cellular material; the improvement comprising blending in said reaction mixture a proportion of comminuted, flexible polyurethane foam scrap having a maximum particle size of less than about 600 microns to form a suspension in said reaction mixture, said proportion of scrap being from about 3 to 40 parts, by weight, based on 100 parts of total polyol weight.     
     
     
       13. The process of claim 12, wherein said polyol is a polyether polyol. 
     
     
       14. The process of claim 13, wherein said reaction mixture further comprises a surfactant. 
     
     
       15. The process of claim 14, wherein said foam scrap is employed in a proportion ranging from about 8 to about 24 parts, by weight, based on 100 parts of total polyol weight. 
     
     
       16. The process of claim 15, wherein said foam scrap is flexible, compression-densified polyurethane foam having a density within the range from about 1.5 to about 15 pounds per cubic foot. 
     
     
       17. The process of claim 16, wherein said polyether polyol is an oxyalkylated polyhydric alcohol having a molecular weight of about 1,000-6,000 and said organic polyisocyanate is toluene diisocyanate. 
     
     
       18. The process of claim 17, wherein said polyether polyol is oxypropylated glycerin and said reaction mixture comprises water and a catalyst mixture of an amine and a stannous salt. 
     
     
       19. A polyurethane foam product prepared according to the process of claim 1. 
     
     
       20. A polyurethane foam product prepared according to the process of claim 8. 
     
     
       21. A polyurethane foam product prepared according to the process of claim 11. 
     
     
       22. A polyurethane foam product prepared according to the process of claim 12. 
     
     
       23. A polyurethane foam product prepared according to the process of claim 18.